1. Field of the Invention
The present invention relates generally to the field of mechanical power transmission via a pulley or other rotating mechanical element mounted on a stationary or dead shaft. More particularly, the invention relates to a dead shaft arrangement including instrumentation for monitoring a plurality of parameters relating to operation of the mechanical element. The invention also relates to an instrumented dead shaft configured to be incorporated into a control and monitoring system.
2. Description of the Related Art
An array of structures are known in the art of mechanical power transmission for supporting a machine element, such as a pulley, in rotation on a machine frame. Applications for such structures include belt drives and conveyors, as well as a wide range of other systems. In general, such structures typically either employ a rotating or "live" shaft, or a stationary or "dead" shaft. In live shaft structures, the machine element is mounted in a fixed position with respect to a shaft, and the shaft is supported for rotation on bearings secured to the machine frame. In dead shaft structures, the shaft is secured to the machine frame and the rotating machine element is supported by bearings on the shaft.
Advances in industrial automation have prompted the need to integrate mechanical power transmission structures of this type more completely with other components, including centralized and distributed control and monitoring systems. Modem industrial automation systems commonly allow for networking of large numbers of sensors and actuators linked to virtually all segments of a plant or installation. Such large scale integration greatly facilitates monitoring and coordination of plant processes, and permits plant personnel to plan for scheduled and unscheduled maintenance of the machine systems. For rotating machinery, parameters of particular interest might include running temperature, speeds, loads, stresses, lubrication conditions and so forth,
Despite the increasing need for feedback information on the operating condition of mechanical transmission components, equipping such components with appropriate instrumentation to collect the information poses significant difficulties in many applications. For example, while certain instrumentation, such as magnetic or inductive proximity switches for indicating rotational speed, may be designed into certain applications, other sensors are more difficult to place due to the particular geometry of the equipment. This is particularly true of load and temperature sensors. Moreover, even where various sensors can be individually placed on separate machine elements, these must generally be wired separately to input devices for incorporation into a control and monitoring network, adding to the cost and complexity of instrumenting the machine.
There is a need, therefore, for a technique for instrumenting rotating machinery that offers a range of operating parameter information through a relatively straightforward interface. In particular, there is a need for an instrumented dead shaft for use with pulleys and other rotating machine elements that is capable of providing information relating to parameters such as rotational speed, bearing temperature, and load or stress. The shaft should ideally be available as a packaged unit with one or more of the instruments installed. The shaft should also be capable of integration with a networked monitoring and control system for remotely detecting the sensed parameters.